This disclosure relates to providing powered accessory devices for headsets.
U.S. Patent Publication 2010/0260361, fully incorporated herein by reference, describes a headset with a modular connection allowing a down-cable, optionally supporting a boom microphone, to be connected to either ear cup, with a crossover plug connected to the opposite ear cup to connect an audio signal provided by the down-cable to the acoustic driver in the ear cup to which the plug is connected. FIGS. 1A and 1B are derived from FIGS. 1 and 4 of that publication. As shown in FIG. 1A, the system incorporates a headset assembly 10, a down-cable assembly 20 and a crossover plug 30. The headset assembly 10 incorporates a first ear cup 12a having an acoustic driver 14a and a connector 16a (both seen more clearly in FIG. 1B), a second ear cup 12b having an acoustic driver 14b and a connector 16b, and a headband 18 that couples together the ear cups 12a and 12b. The down-cable assembly 20 incorporates an electrically conductive cable 22, an upper coupling 24 to couple one end of the conductive cable 22 to either of the connectors 16a and 16b, a communications microphone 26a, a microphone boom 26b coupling the microphone 26a to the upper coupling 24, and a lower coupling 28 for connecting the other end of the conductive cable 22 to another device (not shown) such as an aircraft communications panel, a mobile phone, or a portable radio. The plug 30 is able to be coupled to either of the connectors 16a and 16b. 
As shown in FIG. 1B, multiple electrical conductors (e.g., electrical cabling or other form of electrical conductors) are carried by the headband 18 to convey electrical signals between the earpieces 12a and 12b. Power and ground conductors 40 and 42 are connected to corresponding conductors 50 and 52 in the upper coupling 24 of the down-cable 20 via terminals 60a and 62a in the connector 16a. The power and ground conductors 40 and 42 are also connected to power and ground terminals 60b and 62b in the second ear cup 12b so that the down-cable 20 can be connected to that ear cup instead and still provide power to the headset. The power and ground conductors 40 and 42 provide power to first power electronics 64a in the first ear cup 12a and second power electronics 64b in the second ear cup 12b. A crossover conductor 44 is connected to crossover terminals 66a and 66b in corresponding ear cup connectors 16a and 16b, but is not electrically coupled to anything else within either ear cup. The connectors 16a and 16b have left and right audio signal terminals 68a and 68b, respectively, coupled to the acoustic transducers 14a and 14b. 
In the example of FIG. 1B, a crossover conductor 46 in the crossover plug 30 connects the crossover terminal 66b to the right audio signal terminal 68b in connector 16b. In the upper coupling 24 of the down-cable 20, a left audio conductor 54 is coupled to the left audio signal terminal 68a in the connector 16a, while a right audio conductor 56 is connected to the crossover terminal 66a, from which the crossover conductor 44 conducts the right audio signal to the crossover terminal 66b in the connector 16b. In this way, the crossover conductor 46 couples the right audio from the crossover terminal 66b to the right audio terminal 68b. If the down-cable 20 and crossover plug 30 were reversed, the right audio conductor 56 would be connected directly to the right audio terminal 68b to deliver audio signals to the right transducer 14b (via the power electronics 64b), while the crossover conductors 44 and 46 would couple the left audio signals from the to the left audio conductor 54 to the left audio terminal 68a through the crossover terminals 60a and 60b. This allows the down-cable 20 to be connected to either ear cup, without having to provide both left and right signals across the headband, and without any need to detect which side the down cable is connected to.
The design described in publication 2010/0260361 is implemented commercially in the A20® Aviation Headset from Bose® Corporation of Framingham, Mass.